1. Field of the Invention
The present invention relates to integrated circuit packaging and more particularly to a self-aligning integrated circuit package.
2. Description of the Prior Art
Modern automated techniques for manufacturing integrated circuits have resulted in a substantial reduction in the cost of integrated circuit chips. A substantial portion of the cost of a completed integrated circuit device is attributable to packaging. The high cost of packaging integrated circuits primarily results from the difficulty encountered in making electrical contact to the integrated circuit chip. Some usuable form of lead must be brought out from the small contact pads of the integrated circuit.
The semiconductor industry has established standard lead configurations; however, these leads must be electrically connected to the contact pads on the circuit chip. Many schemes have been devised for connecting the leads to the contact pads; however, the practice of using fine interconnecting wires still prevails as the industry standard.
The standard practice was to bond fine gold or aluminum wire leads to the contact pads on the chip and to the individual leads of a standard lead configuration. This procedure required at least 28 separate bonding steps which resulted in high labor cost. The use of gold wire leads also resulted in high material cost and other technical difficulties such as the purple plague.
In an attempt to eliminate the need for wire leads, the contact frame leads were bonded directly to the contact pads on the chip. This procedure resulted in some success but required larger size contct pads and resulted in increased chip size.
Another solution described in U.S. Pat. No. 3,676,922 proposed the use of a conductive metal sheet spread over the chip and leads and bond thereto to interconnect the contact pads on the chip to the leads. Thereafter, the undesired portions of the conductive metal sheet were removed using a standard photo-resist and etching technique. This procedure allowed for the use of standard lead frames and contact pads; however, the interconnecting metal sheet was relatively thin and not strong enough for all applications.